Process for the preparation of nitrohalo polymers



PROCESS FOR THE PREPARATION OF NITRO- HALO PULYMERS Gustave B. Bachman,West Lafayette, Ind., and Ted J. Logan, Cincinnati, Ohio, assignors toPurdue Research Foundation, Lafayette, Ind, a corporation of Indiana NoDrawing. Application February 14, 1958 Serial No. 715,203

11 Claims. c1. 2 60-2) 7 where X is halogen, and n is an integer, byreacting a 1,2-dihalogenated-1-nitroethane having the structural formulaWhere X is halogen, with a base.

Among the 1,2-diha1ogenated l-nitroethanes which are operative in ourprocess are 1,2-difluoro-l-nitroethane, 1,2- dichloro-l-nitroethane,1,2-dibromo-l-nitroethane, 1,2-diiodo-l-nitroethane,Z-bromo-l-chloro-l-nitroethane, 1- bromo-Z-iodo-l-nitroethane, etc.

The 1,2-dihalo-l-nitroethane used in our process can be prepared in anumber of ways, for example by the addition of halogens to nitroolefins(Wieland and Sakellarios, Ber., vol. 525, p. 903 (13 C.A. 2874)) and (B.Askenasy and V. Meyer, Ber., vol. 25, 1708 (1892)), the condensation offormaldehyde with halonitromethanes, followed by halogenation of thealcohol with PCl (W. Steinholf and M. Kuhnel, Ber., 75B, l329-30(1942)), the vapor phase halonitration of vinyl halides (PhD. thesis ofTed J. Logan, Purdue University (1958)), etc.

The bases which can be utilized in our process may be organic orinorganic. We found alkali metal hydroxides, such as potassium or sodiumhydroxide; alkaline earth metal hydroxides, such as barium or calciumhydroxide; various carbonates, such as calcium carbonate, sodiumbicarbonate, etc.; organic amines, such as the lutidines; etc. to beuseful in our process. We prefer to use carbonates as the basicmaterials utilized in our process due to the fact that they do notinterfere with polymer recovcry and they allow the reaction to go tocompletion.

The process of our invention is operative at room temperature andpressure. It is preferred to maintain the reaction temperatures at belowabout 20 C. and in processes where brorno and iodo nitroethanes or whereorganic amines are utilized, it is preferable to maintain thetemperature at least as low as 0 C. There is little polymer formation ifthe reaction is carried out at a temperature much in excess of about 20C. We have found that We can obtain an 86% polymer recovery with a 1:1molar 2,913,423 Patented Nov. 17, 1959 ratio of dihalogenatednitroethane to basic material during reactionperiods of several hours.

We have found that the polymers prepared by the process of our inventionare moldable plastics of greatly reduced inflammability having the samegeneral utility as the vinyl polymers. The plastics of our invention areeasily deposited on cellulosic fabrics or paper which have beentreatedwith a 50% base solution for several hours by dissolving the polymer ina 50% ethanol solution, pure l,2-dichloro-1-nitroethane,. etc., to theextent of about 10% by weight of polymer to solution. The polymerdeposits on the base treated textile as the textile is passedthrough'the polymer solution. The textile or paper is then dried andrequires no further treatment.

The following examples further illustrate our invention, and it is notintended that the invention be restricted to the procedures,.proportions, or compounds described thereimbhtratherit is intended forall equivalents obvious to those'skille'd' in the art be included withinthe scope of our invention.

Example I To prepare a nitrochloro polymer 0.05 mole of sodiumbicarbonate was added to ml. of water and 0.05 mole of1.2-dichloro-1-nitroethane then slowly added to the bicarbonatesolution. Carbon dioxide began to bubble off immediately and the waterbecame yellow, then red. The bottom, organic layer slowly disappearedand the polymer appeared in the water layer. The mixture was allowed tostand overnight and the polymer was removed from the reaction mixture byfiltration. The polymer was washed eight times with dilute hydrochloricacid. This treatment changed the red coloration of the polymer to acream color. The solid was then redissolved in hot glacial acetic acidand reprecipitated with water. On heating liquid appears on the polymersurface at 118 C.; it forms a clear yellow liquid at 187 C. and becomesblack at 218 C. An 86% yield of the polymer was obtained.

Example II Example III The following table sets out various nitrohalopolymers which can be prepared by the procedure of Example I wherein thedescribed base is reacted with the described dihalonitroethane.

Polymer Base 1,2-dihalo-1-nitroalkane Bromonitropolymer... KOH1,2-dibromo-l-nitroethane.

Do H003. 1bromo-2iodo1nitroethane. Fluoronitropolymer-.. NaHCOa.1,2-difiu0ro-1-nitroethane. Iodonitropolymer NaHOOs.. 1,2'diiodo1nitr0ethane. Chloronitropolymer... N(CHa)a.-l-ehloro-Z-bromo-l-nitroethane.

In general, we prefer to carry out our reaction under weakly basicrather than strongly basic conditions as the latter tend to destroy thedesired end products. As the reaction temperature is increased theactivity of the base is increased.

Now having described our invention what we claim is:

l. A process for the preparation of geminal nitrohalo polymers whichcomprises reacting under weakly basic equimolar proportions a1,2-dihalo-1-nitroethane with a base; and recovering the polymersthereby formed.

2. A process for the preparation of nitrohalo polymers which comprisesreacting under weakly basic conditions at below about 20 C. and inapproximately equimolar proportions a 1,2-dihalo 1 nitroethanewith 'aninorganic "base, and recovering the polymers thereby formed.

3. Theprocess of claim 2 wherein the inorganic base is an inorganiccarbonate.

4i The process of claim 2 wherein the inorganic base is an inorganicbicarbonate. I

5.. The process of claim 2 wherein the inorganic base 'is an alkalimetal hydroxide. 1 I i 6. The process ofclaim 2 wherein the inorganicbase -is an alkaline earthmetal hydroxide. V V I '7. The process for thepreparation of nitrohalo polymers which comprises reacting a 1,2-dihalo-1-nitroethane with a tertiary amineat below about 20.Cgandjnapproximately equimolecular proportions andrecovering thepolymers thereby formed. 1 y L j 8. A process for the production ofnitrofluoro polymers which'comprises reacting a1vfluoro-2rhalo=l-nitroethane V 4 with an inorganic base at below about20 C. and in approximately equimolecular proportions and recovering thepolymers thereby formed.

9; A process for the preparation of nitrochloropolyrners which comprisesreacting a 1-chloro2-halo-1-nitroethane with an inorganic base atbelowabout 20 C. and in approximately equimolecular proportions andrecovering the polymers thereby formed. x

10.A'process for the production of nitrobromo polymers which comprisesreacting a 1-bromo-2-halo-1-nitroethane with an inorganic base at belowabout 20 C. and in approximately equimolecular proportions andrecovering the polymers thereby formed.

11. A process'for the production. of nitroiodo, polymers which comprisesreacting a 1-iodo-2-ha1o-1-nitroethane with an inorganic base at belowabout 20 C. and in approximately equimolecular proportions andrecovering the polymers thereby formed.

7 References Cited in the file of this patent Wieland et al.: Ber., vol.52B, page 903.

1. A PROCESS FOR THE PREPARATION OF GEMINAL NITROHALO POLYMERS WHICHCOMPRISES REACTING UNDER WEAKLY BASIC CONDITIONS AT BELOW ABOUT 20*C.AND IN APPROXIMATELY EQUIMOLAR PROPORTIONS A 1,2-DIHALO-1-NITROETHANEWITH A BASE, AND RECOVERING THE POLYMERS THEREBY FORMED.